1. Field
The present invention relates to a robot, and more particularly to a walking robot with a plurality of legs, which walks using the plurality of legs, and a method of controlling the same.
2. Description of the Related Art
In general, robots are machines which conduct motions similar to those of a human. Early robots were industrial robots, such as manipulators or transfer robots for automation and unmanned production. Recently, a walking robot, which models the biped walking of a human, has been researched and developed. The biped walking robot has disadvantages, such as instability and difficulty in pose control or walking control, as compared with the quadruped or hexapod walking. However, the bipedal robot has advantages, such as more flexibly coping with an uneven surface of ground (i.e., a rugged road) or a discontinuous walking surface (for example, stairs).
In an impedance control method, which is one of methods of controlling a walking robot, positions and angles of ankles are changed in proportion to forces measured by force/torque (F/T) sensors respectively installed on soles of the feet, and thus the feet are stuck to the ground. The impedance control method lowers the stiffnesses of ankle joints and thus has a weak supporting force by the ground and accompanies the tilt of a torso. The impedance control method uses a fixed impedance control gain, and thus causes a walking robot to unstably walk on ground having various prominences and depressions. Further, the impedance control method measures and uses only the repulsive force from the ground, and thus the feet of the walking robot do not stick strongly to the ground. Moreover, the impedance control method estimates the tilt of a torso through ZMP calculation, and thus it is difficult to precisely correct the tilt of the torso.